This invention relates to the formation of images. In particular, this invention relates to the formation of an image using a photosensitive element comprising a layer having a dominant attribute and a layer comprising a colorant applied thereon, and subsequent transfer of the image to any desired support.
Photosensitive elements used in image-reproduction processes are known in the graphics arts industry. Such elements are usually exposed to actinic radiation through an image-bearing transparency, such as a color separation transparency, to produce an image which is either a positive or negative with respect to the transparency used.
Such photosensitive elements are widely used in off-press color proofing to simulate the images produced by printing. In a surprint proof, all of the colored images are superimposed, by, for example, multiple exposure, lamination, or transfer, onto a single support. Unlike an overlay proof, the colored images cannot be separated and viewed individually.
Various processes for producing copies of images involving photopolymerization and thermal transfer techniques are known as disclosed in U.S. Pat. Nos. 5,616,439 and 5,532,115. In these processes, a photopolymerizable layer coated on a suitable support is imagewise exposed to a photographic transparency. The surface of the exposed layer is then pressed into contact with the image receptive surface of a separate element, and at least one of the elements is heated to a temperature above the transfer temperature of the unexposed portions of the layer. The two elements are then separated whereby the thermally transferable unexposed image areas of the composite transfer to the image receptive element. If the element is not precolored, the tacky, unexposed image may now be selectively colored with a desired toner, the application of which could be in film or powder form.
There is a need in the industry to form images having an overall attribute, such as a metallic luster or a fluorescent hue or color saturation. One approach for a metallic or fluorescent appearance is to incorporate into the colored composition a metallic ink or fluorescent ink to achieve an additive effect. However, one problem associated with this is keeping the material having the dominant attribute (fluorescence or metallic) in suspension. In addition, such incorporation may adversely affect the coating quality by decreasing the uniformity and varying the density of the colored composition. Furthermore, the metallic or fluorescent ink may possess certain opacity that adversely affects the desired additive effect of the incorporated colored composition. Color saturation might be accomplished by applying successive ink layers or adjusting colorant proportion. Moreover, any of these known methods for achieving the attributes of color saturation, fluorescence or metallic may adversely affect the color predictability of the incorporated colored composition.
Therefore, it is desirable to develop a process that forms images having an overall attribute but that does not possess the described disadvantages.
This invention provides a process for providing an overall attribute to a photosensitive element.
In one aspect the invention is directed to a process for making an element for forming a final image with an overall attribute by exposure to actinic radiation, the process comprising:
providing a support element having a surface;
applying a first layer having a first surface and a second surface to the surface of the support element, the first surface of the first layer being adjacent to the surface of the support element and the second surface of the first layer being opposite the first surface;
applying, prior to image-wise exposure to actinic radiation, a second layer adjacent to the second surface of the first layer, the second layer having an inner surface and an outer surface, the first layer comprising a photosensitive composition and a feature which imparts a dominant attribute to the first layer, the feature being selected from the group consisting of a fluorescent feature, a metallic feature, an opacity enriching feature or combination of at least two of the foregoing features, the second layer comprising a first colorant;
wherein the overall attribute of the final image is defined by the dominant attribute of the first layer.
The first layer may include a first photosensitive composition, with the second layer including a second photosensitive composition.
The feature which imparts a dominant attribute to the first layer may be selected from the group consisting of a metallic material, a fluorescent material, an opacity enriching material and combinations of at least two of these features.
The first colorant may be selected from the group consisting of a dye or pigment.
The first layer may comprise a second colorant, which may be a dye or pigment which may be different from the color of the second colorant.
The process may further comprise the step of exposing the element with actinic radiation through a separation transparency having a pattern, the separation transparency applied to the outer surface of the second layer, for a period of time sufficient to form image-wise exposed regions on the first layer; removing the separation transparency and developing the element to produce a pattern which is substantially the same as the pattern of the separation transparency.
The first layer may be adhered to the support element with an adhesive and a release layer may be located between the adhesive and the surface of the support element, the process further comprising the step of, applying a transfer element to the produced pattern; separating the support element from the first layer to reveal the adhesive and adhering the revealed adhesive to a permanent support.
The invention is also directed to a photosensitive element made by the process of this invention.
The invention is further directed to an element for forming a final image having an overall attribute by exposure to actinic radiation, comprising:
a support element having a surface;
a first layer having a first surface and a second surface, the first surface of the first layer being adjacent to the surface of the support element and the second surface of the first layer being opposite the first surface;
a second layer adjacent to the second surface of the first layer and applied prior to image-wise exposure to actinic radiation, the second layer having an inner surface and an outer surface, the first layer comprising a photosensitive composition and a feature which imparts a dominant attribute to the first layer, the feature being selected from the group consisting of a fluorescent feature, a metallic feature, an opacity enriching feature or a combination of at least two of the foregoing features, the second layer comprising a first colorant; wherein the overall attribute of the final image is defined by the dominant attribute of the first layer.
The element may further comprise a separation transparency having a pattern, the separation transparency applied to the outer surface of the second layer wherein exposure of the element to actinic radiation through the separation transparency for a sufficient period of time forms image-wise exposed regions on the first layer resulting in a pattern formed on the element which is substantially the same as the pattern of the separation transparency.
This invention provides for high resolution, high quality, full color surprint proofs having a dominant attribute on virtually any proofing paper stock or other permanent support. It also provides for development during imaging with tap water as the liquid developer to minimize or eliminate concerns regarding toxicity, waste treatment, and corrosion. It also provides for color flexibility and the capability for addition of the colorant-containing composition only to the approximate areas where an image is desired. It also provides for the addition of more than one color to a single layer.